Fluorine segregation in the solid state organisation of the 1∶2 mixed-valence salt of bis(2,2-difluoropropylenedithio)tetrathiafulvalene with the isosteric nickel dithiolene complex

Abstract

Electrooxidation of the nickel dithiolene complex [Ni(F₂pdt)₂]⁻ (F₂pdt²⁻ = 6,6-difluoro-6,7-dihydro-5H-[1,4]dithiepine-2,3-dithiolato) in the presence of the isosteric bis(2,2-difluoropropylenedithio)tetrathiafulvalene 1 donor molecule affords a 1∶2 salt, formulated as [1][Ni(F₂pdt)₂]₂, whose layered structure is isostructural with that of 1, and is characterised by a segregation of the fluorinated moieties into fluorous bilayers. It crystallises in the monoclinic system, space group P2₁/c with a = 15.227(3), b = 4.6395(9), c = 13.098(3) Å, β = 113.96(3)°, Z = 2, R = 0.0388 for 804 reflections with I > 2σ(I). Structural, electronic and micro-Raman studies demonstrate the mixed-valence character of the salt.